During active object manipulation, the finger-object interactions give rise to complex fingertip skin deformations. These deformations are in turn encoded by the local tactile afferents and provide rich and behaviorally relevant information to the central nervous system. Most of the work studying the mechanical response of the finger to dynamic loading has been performed under a passive setup, thereby precisely controlling the kinematics or the dynamics of the loading. However, to identify aspects of the deformations that are relevant to online control during object manipulation, it is desirable to measure the skin response in an active setup. To that end, we developed a device that allows us to monitor finger forces, skin deformations, and kinematics during fine manipulation. We describe the device in detail and test it to precisely describe how the fingertip skin in contact with the object deforms during a simple vertical oscillation task. We show that the level of grip force directly influences the fingerpad skin strains and that the strain rates are substantial during active manipulation (norm up to 100%/s). The developed setup will enable us to causally relate sensory information, i.e. skin deformation, to online control, i.e. grip force adjustment, in future studies.

中文翻译：

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在主动对象操作期间测量指垫变形

在主动对象操作期间，手指与对象的交互会导致复杂的指尖皮肤变形。这些变形又由局部触觉传入编码，并为中枢神经系统提供丰富的行为相关信息。大多数研究手指对动态负载的机械响应的工作都是在被动设置下进行的，从而精确控制运动学或负载的动力学。然而，为了识别与对象操纵期间的在线控制相关的变形方面，需要在活动设置中测量皮肤响应。为此，我们开发了一种设备，使我们能够在精细操作过程中监测手指力、皮肤变形和运动学。我们详细描述了该设备并对其进行了测试，以精确描述与物体接触的指尖皮肤在简单的垂直振荡任务中如何变形。我们表明，握力水平直接影响指垫皮肤应变，并且在主动操作期间应变率很大（标准高达 100%/s）。开发的设置将使我们能够在未来的研究中将感官信息（即皮肤变形）与在线控制（即握力调整）因果关联。